Pulp shredder



Dec. l0, 1935. J. J. WARREN PULP SHREDDER Filed Feb. 1o, 1954 2 Sheetsf-Sheet 1 ATTORNEYS Dec. ,10, 1935. J. J. WARREN PULP SHREDDER Filed Feb. 1o, 1954 2 Sheets-Sheet 2 INVENTOR A www BY pm bm/1;, wc

ATTORNEYS Patented Dec. l0, 1935 UNITED STATES PlrrisN'rv OFFICE mass This inventim relates to machines for shredding pulp and similar materials and has for its"v object the provision of improvements in the lmeans for feeding the pulp to the shredder ,i blades.

Pulp Shredders in common use today are provided with a pair of cooperating feed rolls between which the pulp laps are fed, and passed over a bed plate to a rapidly rotating `shredder 1o drum. These feed rolls move the pulp forward at a fixed rate thus limiting the quantity of pulpshredded per unit time and insuring uniformity of product, but only as long as any pulp remains between them. After the tail of a lap or sheet .15 passes the nip of the rolls nothing remains to retard its forward movement but the inconsiderable friction of the bed plate. Consequently,

the last few inches are frequently whipped forward by the shredder and appear as unshredded lumps in the stock.

In order to cure this defect in pulp shredding and td improve'the qualityof the stock, I have, in accordance with the present invention, provided means for positively gripping the entire length of each section of pulp and feeding it to the shredder blades at a uniform rate so that the last few inches are subjected to the same shredding action as the first. In doing this, I have eliminated the xed bed plate, have moved the yshredder drum toward the feed rolls so that the lower roll'becomes in effect a moving bed plate, and have so constructed the feed rolls that the pulprin passing between them is pressed against projections onv the face of the lower roll .and the entire lap. including the tail, positively fed to- 50 Fig. 5 is a sectional view on the line 5 5 of' Fig. 3.

Referring to thedrawings, the shredding ma chine illustrated includes a bed Il having a platform i| on one end of which is mounted a coni; v'eyor assembly of any conventional type. Preferably the conveyor is ofthe roll type andcoml prises a series ofnarrow rolls I2 mounted on the shafts i3 and spaced along the shafts in alignment to form rows extending lengthwise of the machine. The rows of rolls `are separated by 5 longitudinal bars i4 which are` bent at their ends and secured to tlre machine bed, thebars forming a frame to prevent the material from falling down between the rolls. 'I'he shafts il are supported in bearings in the boxes I5 mount- 10 ed on the platform on opposite sides ofthe machine. The conveyor rolls carry the pulp to a pair of cooperating feed rolls I6 and `|1 respectively, andthe feed rolls advance the pulp to a high speed rotary shredder drum, designated 15 generally as Il, which is driven through a pulley i! from an electric motor or other suitable power source. not shown. The shredder drum is of a conventional type and comprises a sries of circular saw blades 2l having large teeth 2i, the 20 saws being spaced along the drum shaft by cast iron or other spacers to suit the feedrolls`-or material to be shredded. 'I'he shreds from the pulp lap fall against a backboard 22 secured to thebedofthemachine. '25 It is desirable, in order thatthe pulp be fed to theshredding drum at an even rate, that the feed rolls and conveyor rolls be driven at the same surface speed, and to lthis end I prefer'to use a variable speed driving motor 23 secured to. 30 the bed' of the machine andconnectedv through worm and wheel, 2l and reduction gearing to the lower feed roll Il,l which in turn is geared to preserves the speed ratio between these members. The sprocket .wheels and driving chain are concealed in a suitable housing 2! secured to the machine bed. The pulp after passing through the nip of the feed rolls is advanced into the paths of the rotating shredder blade teethgll. No stationary bed plate is employed. The blades travel at a high speed relative to the-feeding movement of the rolls, and if means were not provided to grip the pulp after it has passed the nip of the rolls,

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dlowtornrhonmthicknesotthepulppassin: portions the material passing through @he rolls, said second roll having a plurality of openings in the cylindrical surface thereof for receiving the projecting portions passing into the pulp, the projecting portions carrying the material into the paths of said working elements.

5. In a pulp shredder, the combination of a rotary shredding drum having a plurality of working elements extending from the periphery thereof, and cooperating feed rolls adjacent to said rotary drum, said feed rolls including a roll having projecting portions disposed in axially spaced rows around the Vperiphery thereof and teeth on the cylindrical surfaceof the roll between said rows ofprojecting portions, and a second roll cooperating with said iirst roll for.

impaiing on said projecting portions and said teeth the material passing through the rolls, said first roll carrying the material into the paths of` said working elements.

6. In a pulp shredder, the combinationv of a pair of cooperating feed rolls which includes a lower roll comprising a shaft, a plurality of circular discs mounted on the shaft and having projecting portions extending from the peripheries thereof, and spacers interposed between the circular discs, and an upper roll having a plurality of openings disposed in the cylindrical surface thereof and arranged in axially vspaced rows t j a thereof,l and cylindrical spacers interposed between the discs and provided with teeth on the cylindrical surfaces thereof, andan upper roll having a plurality of Openings disposed in the cylindrical surface thereof and arranged in axially spaced rows aligned with said discs for receiving the projecting portions thereon.

8. In a pulp shredder the combination of a rotary shredder drum anda pair of rolls for feeding separate sections of pulp to the drum, one 10 of the rolls being provided with spikes for impal ing and gripping eachsection throughout its entire length and feeding it tothe drum, means permitting automatic adjustment of the distance between the feeding rolls and means for im- 16 parting a peripheral speed to the shredder drum greatly in excess of that of the feed rolls.

9. In a shredding machine the combination of a rotary shredding drum comprising a plurality of spaced saw-toothedv blades, cooperating feed 2o rolls adjacent said shredding drum for feeding separate sections of material thereto, one of said feed rolls having axially spaced rows of peripheral spikes, the other feed roll cooperating with the rst for impaling on said spikes the material 25 passing between the rolls, whereby each section of material is gripped throughout its length as it 'is'fed to the shredding drum, said saw-toothed shredding blades being spaced so as to pass between the spikes on the first feeding roll and 30 extend substantially to the base thereof, and means for rotating the shredder drum at a peripheral speed `much greater than that'of the feed rolls.

JOHN J. WARREN. f 

